"Today, the U.S. Food and Drug Administration announced it has approved the use of Plan B One-Step (levonorgestrel) as a nonprescription product for all women of child-bearing potential. This action complies with the April 5, 2013 order of the Uni"...
MECHANISM OF ACTION — Combination hormonal contraceptives inhibit ovulation via a negative feedback mechanism on the hypothalamus, which alters the normal pattern of gonadotropin secretion of a follicle-stimulating hormone (FSH) and luteinizing hormone by the anterior pituitary. The follicular phase FSH and midcycle surge of gonadotropins are inhibited. In addition, combination hormonal contraceptives produce alterations in the genital tract, including changes in the cervical mucus, rendering it unfavorable for sperm penetration even if ovulation occurs. Changes in the endometrium may also occur, producing an unfavorable environment for nidation. Combination hormonal contraceptive drugs may alter the tubal transport of the ova through the fallopian tubes. Progestational agents may also alter sperm fertility.
Last reviewed on RxList: 12/8/2004
This monograph has been modified to include the generic and brand name in many instances.
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